Ignition apparatus



Dec. 302

R. P. MOCLELLAND ETAL 2,624,018

IGNITION APPARATUS Filed April 2, 1948 w Ar\ [u l 5 C) C [l "1 k n Q o D f w BY @um /wMfw/U Patented Dec. 30, 1952 IGNITION APPARATUS Richard I. McClelland, Sidney, and Warren E.

Kishbaugh, Unadilla, N. Y., assignors to Bendix Aviation Corporation, New York, N. Y., a

corporation of Delaware Application April 2, 1948, Serial No. 18,676

(Cl. S10- 70) l2 Claims. l

This invention relates to ignition apparatus and more particularly to magnetos for generating electrical energy for the ignition systems of engines or the like.

One of the objects of the present invention is to provide -a novelly constructed magneto generator which consists oi parts that may be readily and inexpensively made and assembled.

Another object of the invention is to provide a device of the above character wherein the coil is mounted and secured in place in a novel manner.

A further object is to provide a novelly constructed circuit breaker cam and a novel method of constructing the same.

Still another object is to provide .a magneto generator wherein a circuit breaker cam is combined with lthe current generating rotor in a novel manner.

The above and further objects and novel features of the invention will more fully appear from the following detailed description when the same is read in connection with the accompanying drawings. It is to be expressly understood, however, that the drawings are for the purpose of illustration only and are not intended as a denition of the limits of the invention.

In the drawings, wherein like reference characters refer to like parts throughout the several views,

Fig. 1 is a side elevation, partly in section and with parts broken away, showing one form of magneto in which the invention is embodied.

Fig. 2 is an end view with the cover removed and with parts broken away, the view being taken from the right in Fig. l; and,

Pig. 3 is a detail view on an enlarged scale snowing the novel coil fastening means.

In the form illustrated in the drawings, by way of example,-the invention is embodied in ya small magnetov adapted for use on a single cylinder engine, but the same may be embodied in magnetos for multicylinder engines also. As shown, the structure comprises a casing which consists of a main or central part l0, a front cover Il with a mounting ange I2 and a back cover I4. The front face of casing member lll is open at the bottom only to receive the pilot portion of cover Il, while the depending portion I5 of said face serves as supporting means for the coil and stator poles to be hereinafter described. The rear of member I0 is open at the top to receive the coil and has a web or partition I6 lacross the bottom thereof to serve as a support for one end of the rotor shaft and for the condenser and circuit breaker.

The energy generating means comprises the magnetic rotor I'i which is supported by a ball or roller bearing i8 in cover il and a plain bearing I9 in web i6. For a single cylinder engine the rotor may preferably be of the type shown in Scott Patent No. 2,129,633. When the device is to be used on larger engines or for other purposes, the rotor may be constructed in accord ance with principles well understood in the art. The rotor cooperates in a well known manner with a pair of laminated stator poles 20, 2 l, each of which is shown as being mounted on the front face l5 of casing member l0 by means of a pair of rivets 22 (Fig. 2). A transformer coil 23 is found on :a laminated metal core 24, the ends of which rest upon the upper ends of stator poles 20, 2l. Lateral movement of the coil and core is resisted by the edge to edge engagement of the core `and stator pole laminations.

Novel means are provided for securing the coil and core in position, said means being adapted for application from outside the casing, thereby making it possible to reduce the size of the casing in a minimum. Said means also provides a resilient or cushion mounting for reducing the ill effects of vibration and obviating any excessive strain upon the mounting means 22 for the stator poles. As illustrated, said coil securing means comprises a stiff helical spring 25 or the like, held under compression against the upper face of each end portion of core 24 by a set screw 26. Said screws and springs are contained in tapped holes 21 in bosses formed inside of casing member l0. Said bosses extend relatively close to the upper surface of core 24 so that only a small part of each spring 25 projects out of hole 21 to thus prevent any tilting thereof. To obviate any danger of the springs becoming anchored or caught in the threads in holes 21, said threads and the helices of the springs are of the opposite hand; that is, one is right and the other is left. In order to prevent the entrance of moisture which might cause corrosion and, hence, a binding of the threads on screw 26, the head on the latter is provided with a bevelled lower surface to engage a similar seat 28 at the outer end of hole 2. The parts are so proportioned that when the screw is seated at 28, the spring 25 is not fully compressed. The force of the compressed springs is suilicient to hold the coil in position while insuring against any undue strain upon rivets 22 and reducing the harmful eiects of vibration and shock upon the coil structure.

In the further interest of simplicity and reduction in size, the high potential or output end of the secondary winding of coil 23 is connected with an outside conductor 29 through a resilient adaptor or boot 39. The latter has :a cradle portion 3l which engages one side of the coil and a housing portion 32 which extends through a slot provided in the face portion l of housing member l0. The coil and boot may thus be assembled and mounted in or removed from the casing as a unit without the necessity for making an electrical connection inside the casing. The coil is grounded through a lead 33 and the primary winding is connected to the insulated contact of a circuit breaker through lead 35.

A circuit breaker 35 is mounted on the wall or web I6 for bodily adjustment about the axis of rotation of rotar shaft 36 on the projecting end of which a cam 3l is formed for operatingv the circuit breaker in a manner well understood in the ignition art. The circ-uit breaker comprises a bracket 38 which carries `a normally fixed lcontact 39, a spring mounted movable contact di) and a spring mounted cam follower 4l on which a lubricating wick d2 may be mounted. Bracket 33 is pivotally secured at t3 on a plate #lll which is in turn mounted on web l by means of screws 46, 47 that extend through curved slots in the plate to render the entire assembly angularly adjustable as mentioned above. The other end of bracket 38 is secured to plate l by a screw 11S that extends through a curved slot iin the bracket, thus permitting adjustment about pivot 43. Contact 39 is grounded and contact di) is normally insulated from ground but connected with the coil primary through lead` 34.

The cam provided for operating the circuit breaker is novelly constructed iin a manner which contributes to the simplicity and low cost of the magneto. .Said cam is formed as an integral part of the rotor shaft 36 by first drilling the center portion out of the end of the shaft, if 'it is not already tubular, and then deforming one side thereof as best seen in Fig. 2. The deformed or inwardly bent side i9 of the tubular shaft becomes the low point [of the cam surface and the non-deformed part serves as the lobe which effects periodic separation of the circuit breaker contacts 39, 4D.

Asmail condenser 50 is mounted on. web I6 by means of 'a suitable mounting bracket 5l. Electrically, the condenser is connected across the breaker points 3S, lli! to prevent arcing.

The rear of the casing is closed yby cover ill on A which is mounted a switch for use in preventing operation lof the magneto. Said switch comprises a bolt 52 extending through cover l5 and insulated therefrom by washers 53, 53. The inner end` of bolt 52 supports a spring 513 which engages the insulated side of the Vcircuit breaker when the cover :is in place. A leaf spring 55 providedl with an insulating button 55 is mounted on and electrically connected with bolt 52. Thus when the free end of spring 55 is pressed into engagement with cover lil the eiect is to electrically ground the high potential end of the primary wind-ing of coil 23 and thus prevent the normal functioning. of the magneto.

There is thus provided a novel magneto generator adapted for furnishing the electrical energy for the ignition system of an internal combustion engine and similar purposes. The structure of the magneto thus provided is extremely simple and rugged, the same embodying only a Very small number of parts which may readily and inexpensively be' manufactured and assembled. Contributing to these novel results d are the novel coil mounting and cam construction comprehended by the invention.

Although only a single embodiment of the invention has been illustrated and described in detail, it is to be expressly understood that the invention is not so limited. Various changes may be made in the design and arrangement of the parts illustrated without departing from` the spirit and scope of the invention. For example, other well known types of rotors and circuit breakers may -be provided :in lieu of those sho-Wn.

What is claimed is:

1. A magneto lincluding a rotor, a cam shaft, a circuit breaker riding the cam, stator poles, a coil with core ends resting on the stator poles, a lone-piece casing' member surrounding the said parts, coil springs projecting from the` easing and vbearing on the core ends, and screw threaded means accessible from outside the casing member for applying endwise pressure to said springs.

2. A magneto including `a cam shaft, a circuit breaker riding the cam shafft, stator poles, a coil with core ends resting' on the stator poles, a casing, screw threaded holes drilled in the casing, with machined and counter-sunk ends, screws having machine vheads seated in said countersunk holes, and springs bearing against said screws and against the core ends, the inner ends of said holes being closely adjacent to the spring bearing surfaces of said core ends, whereby said springs are laterally supported throughout substantially the entire lengths thereof by the walls of said holes.

3. A magneto including stator poles, core ends resting on the stator poles, a casing for said parts, screw threaded holes in the casing, coil springs almost wholly contained 4within said holes and bearing on the core ends, the screw threads in said holes being of opposite hand to the coils of said springs, and screws in the holes bearing on the coil springs.

4. In a magneto, a pair of le iinated stator poles, a laminated coil core h, i thc ends thereof seated on said poles, the, laminationsoi said poles being in edge-to-edge contact with the laminations of said core, a one-piece casing member surrounding said poles and core land having internal surfaces close-ly upper surfaces of the ends of the wall thereof and said internal sur a said upper surfaces oi' the core ends, and set screws threaded into -sa-id opmings from outside easing member for compressing said springs.

In a magneto, the combination defined in claim l wherein the construction oi the casing member is such that less than about one turn of each of said coil springs is between said core and the inner surfaces of saidcasng member around said openings.

ln a magneto, a combination as defined in claim 5 wherein the heads of said scr ys have frustro-conical surfaces which sealing engagement with correspondingly shaped countersunk surfaces on said casing member.

'7. ln a magneto, a casing member having an uninterrupted peripheral wall, a pair stator poles mounted in said c .einher7 accil, a core in said coil projecting from opposite ends thereof, the lower surfaces of the ends oi" said core resting on said poles and the opp of said core ends being in close 1 inner wall surfaces of said casing member, casing member having internally threaded passages through the wall thereof above said core ends, a set screw threaded into each of said openings, the head portions of said screws having engagement with said casing member to seal said openings, and al coil spring in each of said openings interposed under compression between said screws and said upper surfaces of said core ends.

8. In a magneto, the combination defined in claim 7 wherein said springs when under compression have an outside diameter only slightly less than the minor diameter of the screw threads in said openings.

9. In a magneto, the combination as dened in claim 8 wherein the pitch of the threads in said openings is of the opposite hand to the Coils of said springs.

10. In a magneto, the combination as dened in claim 7 wherein the surfaces of said casing member engaged by said head portions of the screws are machined surfaces.

11. In a magneto, the combination as dened. in claim 10 wherein said machined surfaces are frustro-conically shaped.

12. In a magneto, the combination as defined in claim 11 wherein said machined surfaces are counter-sunk in the casing member.

RICHARD P. MCCLELLAND. WARREN E. KISHBAUGH.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 965,838 Sanborn July 26, 1910 984,368 Hall Feb. 14, 1911 1,075,987 McMahon Oct. 14, 1913 1,141,336 Hamm June 1, 1915 1,668,442 Wineman May 1, 1928 1,679,069 Brown July 31, 1928 1,695,708 Bugatti Dec. 18, 1928 1,942,123 Reis Jan. 2, 1934 2,016,982 Bradford Oct. 8, 1935 2,110,321 Borgerd Mar. 8, 1938 2,151,955 Crocker Mar. 28, 1939 2,199,907 Barrett May 7, 1940 2,205,047 Nardone June 18, 1940 2,243,418 Crocker May 27, 1941 2,253,201 Schwarzmann Aug. 19, 1941 2,391,854 Hartzell Dec. 25, 1945 

